首页
登录
职称英语
The human species came into being at the time of the greatest biological div
The human species came into being at the time of the greatest biological div
游客
2023-11-04
39
管理
问题
The human species came into being at the time of the greatest biological diversity in the history of the Earth. Today, as human populations expand and alter the natural environment, they are reducing biological diversity to its lowest level. The ultimate consequences of this biological reduction are beyond calculation, but they are certain to be harmful. That, in essence, is the biodiversity crisis.
The history of global diversity can be summarized as follows: after the initial flowering of multicellular animals, there was a swift rise in the number of species in early Paleozoic times (between 600 and 430 million years ago), then plate-alike stagnation for the remaining 200 million years of the Paleozoic era, and finally a slow but steady climb through the Mesozoic and Cenozoic eras to diversity’s all-time high. This history suggests that biological diversity was hard won and a long time in coming. Furthermore, this pattern of increase was set back by five massive extinction episodes. The most recent of these, during the Cretaceous period, is by far the most famous, because it ended the age of the dinosaurs, giving hegemony to the mammals, thus ultimately making possible the dominance of the human species over the Earth. But the Cretaceous crisis was minor compared with the Permian extinctions 240 million years ago, during which between 77 and 96 percent of marine animal species perished. It took five million years, well into Mesozoic times, for species diversity to begin a significant recovery.
Within the past 10,000 years biological diversity has entered a wholly new era. Human activity has had a devastating effect on species diversity, and the rate of human-induced extinctions is accelerating. Half of the bird species of Polynesia have been eliminated through hunting and the destruction of native forests. The list of such biogeographic disasters is extensive.
Because every species is unique and irreplaceable, the loss of biodiversity is the most profound process of environmental change. Its consequences are also the least predictable because the value of the Earth’s species remains largely unstudied and unappreciated; unlike material and cultural wealth, which we understand because they are the substance of our everyday lives, biological wealth is usually taken for granted. This is a serious strategic error, one that will be increasingly regretted as time passes. [br] All of the following contribute to the extinction of species EXCEPT
选项
A、hunting.
B、pollution.
C、deforestation.
D、the growth of human populations.
答案
B
解析
由第三段第三句“在波利尼西亚,有一半的鸟类由于人类捕猎或者当地森林被破坏而消失的”可排除[A]和[C];而根据第一段第二句“人类人口的不断增长以及对自然环境的改变,使物种数量降低到最低水平”可排除[D],因此答案为[B]。
转载请注明原文地址:https://tihaiku.com/zcyy/3157014.html
相关试题推荐
ThatLouiseJohannesisbelievedbymanycriticstobethegreatesttwentiet
ThatLouiseJohannesisbelievedbymanycriticstobethegreatesttwentiet
ThatLouiseJohannesisbelievedbymanycriticstobethegreatesttwentiet
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Thehumanspeciescameintobeingatthetimeofthegreatestbiologicaldiv
Theintroductionofnon-native"exotic"speciesisnowseenasamajorthre
Theintroductionofnon-native"exotic"speciesisnowseenasamajorthre
Beethovenestablishedhimselfasthegreatestcomposer[br][originaltext]B
Beethovenestablishedhimselfasthegreatestcomposer[originaltext]Beethov
随机试题
TheancientAztecsveneratedthecacaotreeanduseditsbeansasaformof
我国近代的三大民营出版机构不包括( )。A.商务印书馆 B.开明书店 C.
B
长为8宽为5的长方形内有一内接阴影四边形(如图所示),则阴影四边形的面积是(
下列选项中,属于拜占庭式建筑典型特征的是()。A.穹顶 B.尖顶 C.歇
关于常用的国外药典叙述错误的是A.美国药典简称USP,现行版为第31版(2008
共用题干 患者女性,50岁,因右上腹痛、发热、黄疸入院。患者就诊6小时后出现高
一般认为,1868年英国成立的“海外及殖民地政府信托基金”是世界上最早的证券投资
治疗高热抽搐、小儿急惊、带状疱疹,宜选用的药物是A.黄芩 B.黄连 C.黄柏
陕西某高校一位副教授因高热住进职工医院。经B超、CT、胃检、抽血、抽骨髓化验等检
最新回复
(
0
)